This lesson will demonstrate how convection currents move materials. It will demonstrate the idea that less dense materials rise above denser materials. The students will learn that heating a material lowers the density of that material, allowing it to rise above the surrounding denser material. As a heated material rises, it distributes its heat to the surrounding cooler material, becoming cool again and sinking back down because it is denser than the other material. This rise and fall of material due to density creates a continuous current known as a convection cell. Convection cells occur in Earth's mantle, causing Earth's lithospheric plates to move.
I chose this lesson to open the unit on volcanoes so that students can begin to learn what is taking place inside of the Earth to cause volcanoes. I will explain to the students that I want them to understand, not only what happens when a volcano erupts, but the reason for why it is erupting in the first place.
Learning Performances
Students will apply what they have learned about convection currents to what is happening in Earth's mantle. They will discuss, answer questions and draw a diagram of what these convection currents look like in Earth's mantle. From this concept, the students will decide how these convection currents are responsible for moving Earth's lithospheric plates.
10 min on opening task
10 min on reviewing questions
20 min on observing the lava lamp/discussion/worksheet
5 min directions for diagrams
30 min drawing diagrams
15 min sharing diagrams
7 min working on homework
Instructional Sequence:
Introducing the lesson
I will introduce the lesson to the students by conducting a class discussion that will require students to answer various questions. From these questions, I will be able to activate and assess the students' prior knowledge. These questions will act as a review of what the students should already understand about density. They must understand the concepts of density before they can understand how convection currents work. I will capture the students' attention by using a lava lamp as a visual of what a convection cell looks like and having the students complete a notes worksheet during the demonstration. I will engage the students in the lesson by making them apply what they have learned about convection cells to the convection cells found in Earth's mantle by drawing diagrams. Each task will be meaningful to the students because they build upon one another and help the students learn new concepts. The assignments are not the exact same material being presented over and over again.
Instructional Activities
I will begin the class by having the students answer some questions in their journal notebooks while I take attendance. The questions will be written on the board in the designated spot which has a different opening task each day. The students are already in the habit of coming into class and beginning this task each day. The questions on the board will be.....
Question: How would you describe density?
Question: How would you describe the molecules in a substance with low density?
Question: What affects the movement of molecules?
After about ten minutes, I will lead the students in a discussion where we would go over the answers to the three previous questions.
Answer: Density is the amount of matter in a certain unit of volume or space.
Answer: The molecules in a substance with low density are sparsely packed.
Answer: Temperature affects the movement of molecules.
At this point I will say to the class “Today we will begin our unit on Volcanoes. To begin our discussions on Volcanoes, I find it important to start by learning what is happening inside of the Earth to create these dangerous mountains and where it is that lava is coming from. I have opened today’s lesson by reviewing what we already know about density. The reason we are reviewing this knowledge is because we can not learn how material moves inside the Earth until we understand the general movement of molecules in a substance. Reaching this level of understanding will help us to visualize how material is moving inside the Earth, and how this movement creates volcanoes. By the end of today’s lesson I want everyone to visualize this movement and then illustrate to me that you have visualized it correctly by drawing me a diagram.”
I will then ask and discuss with the students the following questions and answers...
Question: When the temperature of a substance is increased, what happens to the movement of the molecules? Answer: The movement of the molecules increases when the temperature of a substance is increased.
Question: How would an increase in temperature affect the density of a substance? Explain. Answer: An increase in temperature causes the molecules to move around more quickly. This movement of the molecules will result in a decrease in density because the number of molecules in a certain unit of space or volume would decrease.
At this point I will bring over a lava lamp from behind my desk and plug it in. (It will not take the lava long to start flowing because I will turn it on before class so that it would be warm already) I will explain to the students that the questions we have been answering about density come together in what is know as convection currents, and that the lava lamp is an example of a convection current. I will also hand out a notes worksheet for the students to complete as I go through the demonstration with them. This will provide material for them to study from for the test and will allow me to observe which students are on task and understanding the lesson.
The first question I will ask the students in the discussion is "why do you think that the "lava" is sitting at the bottom of the lamp" and the students will answer that it is because the "lava" is more dense than the other liquid in the lamp. Once the lava begins to rise, I will ask the students to explain or I will lead them to the explanation that the lava is beginning to rise because it is becoming less dense than the surrounding liquid. "How is it becoming less dense?" will be the next question and the students will answer that the light bulb in the base of the lamp is heating the lava, making it less dense.
From here I will note the fact that once the lava rises to the top of the lamp, it begins to sink back down. I will explain to the students that as the lava is rising, it is losing its heat to the cooler surrounding liquid. As it loses this heat, it becomes denser than the surrounding liquid again, and sinks back down to the bottom of the lamp. Note: This is where I will explain the misconception that the lava is losing heat and not getting cold because it is in contact with colder liquid. Cold is not passed on, heat is.
"What happens once the lava has fallen back down to the bottom of the lamp?" Now I will make sure that the students understand that this rising and sinking doesn't only happen once, but that it is a continuous cycle by asking them to observe what happens every time the lava falls back down. I will then tell the students that this cycle of rising and falling is referred to as a convection cell.
From here I will tell the class that this motion is what is taking place in the Earth's mantle. I will ask "what is heating the Earth's mantle?", and the students will answer thecore is hot and heating the mantle. I will then explain that in the mantle, there is uneven heating taking place because some places in the mantle are hotter than other places. Due to this uneven heating, more than one convection cell is occurring in the mantle and there are actually many of these cells throughout Earth's mantle. I will also tell the students that these cells can have a current that is flowing in either a clockwise or counter-clockwise motion. Then I will ask "how do you think convection in the mantle might be related to plate movement?" (from class book) and the students will answer that since the Earth's plates are sitting on top of the mantle, they are moved by the flow of the mantle due to the currents.
It is here that I will pass out one piece of construction paper to each of the students and will ask them to draw a diagram of what they think the convection cells in the Earth's mantle look like. I will ask them to draw a diagram of the whole earth, and to include all of Earth's layers, but to concentrate on drawing the convection cells in the mantle. I will allow the students to reference the diagram of Earth's layers from their textbook. I will suggest the use of arrows to help illustrate the direction of flow. I will allow the students to discuss ideas with their peers, but they must each draw their own diagram. The students will then grab the coloring tools from the bin in the back of the room where they are stored and can begin. While the students are working on these diagrams, I will be walking around the room to answer questions and observe. If it appears that any of the students are not drawing proper diagrams, I will ask them to explain what it is they are drawing and carefully push them into discovering the errors with their work and how to correct it.
After thirty minutes are up I will have the students put away their coloring tools and I will ask for a few volunteers to come up to the front of the room and show off their work and explain what they drew. This will give me an opportunity to praise student work and it will provide another review of the key concepts. Also, if my explanations were unclear to anyone, this exercise could clear up any uncertainties. Sometimes students have a way of explaining concepts to on another in a way that teachers may not think of. I will then assign the students their homework which will be a worksheet on convection that has questions regarding today's concepts. They will also need to finish off their diagrams if they have not done so already. I will allow the students to use the remainder of class to begin this assignment, that way if they have any questions they can ask me before they leave.
Concluding the Lesson
The purpose of this lesson will be reinforced because each activity builds on the previous activity. The students must constantly apply newly learned ideas to different situations, providing the opportunity for the ideas to become meaningful. This lesson relates to issues in the students lives because we all live on earth, and convection in the mantle takes places beneath where we all live. I will also relate this concept to the students' daily lives through some questions in their homework which have them apply convection currents to heat in their houses. The lesson will be brought together through the diagram that the students will draw and through the questions that the students will answer for homework. The main idea of this lesson is that the convection cells in Earth's mantle are responsible for the moving of Earth's lithospheric plates.
Assessing Student Understanding
I will determine if students have met the learning performances by grading their homework assignments and diagrams. Informally, I will be able to determine student understanding based on body language, participation, answers to questions during the class discussion, and by checking to make sure the notes worksheet is being completed correctly as I walk around the room during the demonstration.
Cautions
A common misconception that I must address in this lesson is that some students may believe that the warmer material is cooled down when "coldness" is passed on by touching the colder material. I will make sure that during discussion, the students understand that the warmer material looses its heat by passing its "heat" on to the colder material. In other words, an object looses heat. It does not gain "coldness".
O'Donnell, C. (2000). Science and Technology Concepts for Middle Schools; Catastrophic Events. Burlington, North Carolina: Carolina Biological Supply Company.
According to our reading from the book How Students Learn, one of the first steps in teaching is to engage students' prior learning before beginning a new lesson. Since this is such an important idea, I began my lesson plan by having the students answer a few questions about density. These questions act as a "refresher" of what they already should know about density. Without a true understanding of what density is and what its characteristics are, the students will not be able to apply it properly to the topic of convection currents. After the students have answered the questions, I use a whole class discussion to go over the appropriate answers and ask some more advanced questions that will set the path for the discussion of convection currents.
My second activity is a demonstration of a convection current through the use of a visual, the lava lamp. The three modalities of how students learn are auditory, visually, and kinesthetically. The class discussion with help the auditory learners and this lava lamp will help the visual learners, and using both at once just expands the amount of information that the students are being exposed to. Also, by illustrating a real convection current with the lava lamp, I am helping to design a conceptual framework for the students. When they begin the third activity, they can relate the new ideas of convection cells in the Earth's mantle to the convection cell in the lamp.
The diagram activity provides a way for the students to apply all of facts that they have learned to the "big picture", which is how convection cells occur in the mantle and how, in turn, these cells move Earth's lithospheric plates. Finally, the homework assignment helps the students monitor their learning by asking questions that help them review the concepts they have just learned and by requiring them to apply the concept of convection currents to an everyday situation (heat traveling through a house). As we have discussed in class, meaningful learning takes place when students can relate topics to their everyday lives.
Title:
Convection in the MantleGrade Level:
Grade EightCourse:
General ScienceLesson Overview
This lesson will demonstrate how convection currents move materials. It will demonstrate the idea that less dense materials rise above denser materials. The students will learn that heating a material lowers the density of that material, allowing it to rise above the surrounding denser material. As a heated material rises, it distributes its heat to the surrounding cooler material, becoming cool again and sinking back down because it is denser than the other material. This rise and fall of material due to density creates a continuous current known as a convection cell. Convection cells occur in Earth's mantle, causing Earth's lithospheric plates to move.I chose this lesson to open the unit on volcanoes so that students can begin to learn what is taking place inside of the Earth to cause volcanoes. I will explain to the students that I want them to understand, not only what happens when a volcano erupts, but the reason for why it is erupting in the first place.
Learning Performances
Students will apply what they have learned about convection currents to what is happening in Earth's mantle. They will discuss, answer questions and draw a diagram of what these convection currents look like in Earth's mantle. From this concept, the students will decide how these convection currents are responsible for moving Earth's lithospheric plates.Links to Standards or Benchmarks
Unpacked Learning GoalMaterials Needed
Teacher's Materials:Students' Materials:
Time Required
One 97 minute block10 min on opening task
10 min on reviewing questions
20 min on observing the lava lamp/discussion/worksheet
5 min directions for diagrams
30 min drawing diagrams
15 min sharing diagrams
7 min working on homework
Instructional Sequence:
Introducing the lesson
I will introduce the lesson to the students by conducting a class discussion that will require students to answer various questions. From these questions, I will be able to activate and assess the students' prior knowledge. These questions will act as a review of what the students should already understand about density. They must understand the concepts of density before they can understand how convection currents work. I will capture the students' attention by using a lava lamp as a visual of what a convection cell looks like and having the students complete a notes worksheet during the demonstration. I will engage the students in the lesson by making them apply what they have learned about convection cells to the convection cells found in Earth's mantle by drawing diagrams. Each task will be meaningful to the students because they build upon one another and help the students learn new concepts. The assignments are not the exact same material being presented over and over again.
Instructional Activities
I will begin the class by having the students answer some questions in their journal notebooks while I take attendance. The questions will be written on the board in the designated spot which has a different opening task each day. The students are already in the habit of coming into class and beginning this task each day. The questions on the board will be.....After about ten minutes, I will lead the students in a discussion where we would go over the answers to the three previous questions.
At this point I will say to the class “Today we will begin our unit on Volcanoes. To begin our discussions on Volcanoes, I find it important to start by learning what is happening inside of the Earth to create these dangerous mountains and where it is that lava is coming from. I have opened today’s lesson by reviewing what we already know about density. The reason we are reviewing this knowledge is because we can not learn how material moves inside the Earth until we understand the general movement of molecules in a substance. Reaching this level of understanding will help us to visualize how material is moving inside the Earth, and how this movement creates volcanoes. By the end of today’s lesson I want everyone to visualize this movement and then illustrate to me that you have visualized it correctly by drawing me a diagram.”
I will then ask and discuss with the students the following questions and answers...
Question: When the temperature of a substance is increased, what happens to the movement of the molecules?
Answer: The movement of the molecules increases when the temperature of a substance is increased.
Question: How would an increase in temperature affect the density of a substance? Explain.
Answer: An increase in temperature causes the molecules to move around more quickly. This movement of the molecules will result in a decrease in density because the number of molecules in a certain unit of space or volume would decrease.
At this point I will bring over a lava lamp from behind my desk and plug it in. (It will not take the lava long to start flowing because I will turn it on before class so that it would be warm already) I will explain to the students that the questions we have been answering about density come together in what is know as convection currents, and that the lava lamp is an example of a convection current. I will also hand out a notes worksheet for the students to complete as I go through the demonstration with them. This will provide material for them to study from for the test and will allow me to observe which students are on task and understanding the lesson.
The first question I will ask the students in the discussion is "why do you think that the "lava" is sitting at the bottom of the lamp" and the students will answer that it is because the "lava" is more dense than the other liquid in the lamp. Once the lava begins to rise, I will ask the students to explain or I will lead them to the explanation that the lava is beginning to rise because it is becoming less dense than the surrounding liquid. "How is it becoming less dense?" will be the next question and the students will answer that the light bulb in the base of the lamp is heating the lava, making it less dense.
From here I will note the fact that once the lava rises to the top of the lamp, it begins to sink back down. I will explain to the students that as the lava is rising, it is losing its heat to the cooler surrounding liquid. As it loses this heat, it becomes denser than the surrounding liquid again, and sinks back down to the bottom of the lamp. Note: This is where I will explain the misconception that the lava is losing heat and not getting cold because it is in contact with colder liquid. Cold is not passed on, heat is.
"What happens once the lava has fallen back down to the bottom of the lamp?" Now I will make sure that the students understand that this rising and sinking doesn't only happen once, but that it is a continuous cycle by asking them to observe what happens every time the lava falls back down. I will then tell the students that this cycle of rising and falling is referred to as a convection cell.
From here I will tell the class that this motion is what is taking place in the Earth's mantle. I will ask "what is heating the Earth's mantle?", and the students will answer the core is hot and heating the mantle. I will then explain that in the mantle, there is uneven heating taking place because some places in the mantle are hotter than other places. Due to this uneven heating, more than one convection cell is occurring in the mantle and there are actually many of these cells throughout Earth's mantle. I will also tell the students that these cells can have a current that is flowing in either a clockwise or counter-clockwise motion. Then I will ask "how do you think convection in the mantle might be related to plate movement?" (from class book) and the students will answer that since the Earth's plates are sitting on top of the mantle, they are moved by the flow of the mantle due to the currents.
It is here that I will pass out one piece of construction paper to each of the students and will ask them to draw a diagram of what they think the convection cells in the Earth's mantle look like. I will ask them to draw a diagram of the whole earth, and to include all of Earth's layers, but to concentrate on drawing the convection cells in the mantle. I will allow the students to reference the diagram of Earth's layers from their textbook. I will suggest the use of arrows to help illustrate the direction of flow. I will allow the students to discuss ideas with their peers, but they must each draw their own diagram. The students will then grab the coloring tools from the bin in the back of the room where they are stored and can begin. While the students are working on these diagrams, I will be walking around the room to answer questions and observe. If it appears that any of the students are not drawing proper diagrams, I will ask them to explain what it is they are drawing and carefully push them into discovering the errors with their work and how to correct it.
After thirty minutes are up I will have the students put away their coloring tools and I will ask for a few volunteers to come up to the front of the room and show off their work and explain what they drew. This will give me an opportunity to praise student work and it will provide another review of the key concepts. Also, if my explanations were unclear to anyone, this exercise could clear up any uncertainties. Sometimes students have a way of explaining concepts to on another in a way that teachers may not think of. I will then assign the students their homework which will be a worksheet on convection that has questions regarding today's concepts. They will also need to finish off their diagrams if they have not done so already. I will allow the students to use the remainder of class to begin this assignment, that way if they have any questions they can ask me before they leave.
Concluding the Lesson
The purpose of this lesson will be reinforced because each activity builds on the previous activity. The students must constantly apply newly learned ideas to different situations, providing the opportunity for the ideas to become meaningful. This lesson relates to issues in the students lives because we all live on earth, and convection in the mantle takes places beneath where we all live. I will also relate this concept to the students' daily lives through some questions in their homework which have them apply convection currents to heat in their houses. The lesson will be brought together through the diagram that the students will draw and through the questions that the students will answer for homework. The main idea of this lesson is that the convection cells in Earth's mantle are responsible for the moving of Earth's lithospheric plates.
Assessing Student Understanding
I will determine if students have met the learning performances by grading their homework assignments and diagrams. Informally, I will be able to determine student understanding based on body language, participation, answers to questions during the class discussion, and by checking to make sure the notes worksheet is being completed correctly as I walk around the room during the demonstration.Cautions
A common misconception that I must address in this lesson is that some students may believe that the warmer material is cooled down when "coldness" is passed on by touching the colder material. I will make sure that during discussion, the students understand that the warmer material looses its heat by passing its "heat" on to the colder material. In other words, an object looses heat. It does not gain "coldness".Sources
http://astroventure.arc.nasa.gov/teachers/pdf/AV-Geolesson-4.pdfO'Donnell, C. (2000). Science and Technology Concepts for Middle Schools; Catastrophic Events. Burlington, North Carolina: Carolina Biological Supply Company.
Teaching Resources
Class notes worksheet:
Homework assignment:
Rationale
According to our reading from the book How Students Learn, one of the first steps in teaching is to engage students' prior learning before beginning a new lesson. Since this is such an important idea, I began my lesson plan by having the students answer a few questions about density. These questions act as a "refresher" of what they already should know about density. Without a true understanding of what density is and what its characteristics are, the students will not be able to apply it properly to the topic of convection currents. After the students have answered the questions, I use a whole class discussion to go over the appropriate answers and ask some more advanced questions that will set the path for the discussion of convection currents.My second activity is a demonstration of a convection current through the use of a visual, the lava lamp. The three modalities of how students learn are auditory, visually, and kinesthetically. The class discussion with help the auditory learners and this lava lamp will help the visual learners, and using both at once just expands the amount of information that the students are being exposed to. Also, by illustrating a real convection current with the lava lamp, I am helping to design a conceptual framework for the students. When they begin the third activity, they can relate the new ideas of convection cells in the Earth's mantle to the convection cell in the lamp.
The diagram activity provides a way for the students to apply all of facts that they have learned to the "big picture", which is how convection cells occur in the mantle and how, in turn, these cells move Earth's lithospheric plates. Finally, the homework assignment helps the students monitor their learning by asking questions that help them review the concepts they have just learned and by requiring them to apply the concept of convection currents to an everyday situation (heat traveling through a house). As we have discussed in class, meaningful learning takes place when students can relate topics to their everyday lives.
DEMO LP EVAL - LIZA - JAY
Back to Lesson Sequence